Amalthea (moon)
Greyscale Galileo images of Amalthea
|
|||||||||
| Discovery | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Discovered by | E. E. Barnard | ||||||||
| Discovery date | 9 September 1892 | ||||||||
| Designations | |||||||||
| Adjectives | Amalthean | ||||||||
| Orbital characteristics | |||||||||
| Periapsis | 181150 km | ||||||||
| Apoapsis | 182840 km | ||||||||
|
Mean orbit radius
|
181365.84±0.02 km (2.54 RJ) | ||||||||
| Eccentricity | 0.00319±0.00004 | ||||||||
| 0.49817943±0.00000007 d (11 h, 57 min, 23 s) | |||||||||
|
Average orbital speed
|
26.57 km/s | ||||||||
| Inclination | 0.374°±0.002° (to Jupiter's equator) | ||||||||
| Satellite of | Jupiter | ||||||||
| Physical characteristics | |||||||||
| Dimensions | 250 × 146 × 128 km | ||||||||
|
Mean radius
|
83.5±2.0 km | ||||||||
| Volume | (2.43±0.22)×106 km3 | ||||||||
| Mass | (2.08±0.15)×1018 kg | ||||||||
|
Mean density
|
0.857±0.099 g/cm3 | ||||||||
| ≈ 0.020 m/s2 (≈ 0.002 g) | |||||||||
| ≈ 0.058 km/s | |||||||||
| synchronous | |||||||||
| zero | |||||||||
| Albedo | 0.090±0.005 | ||||||||
|
|||||||||
| 14.1 | |||||||||
Amalthea (/æməlˈθiːə/ am-əl-THEE-ə; Greek: Ἀμάλθεια) is the third moon of Jupiter in order of distance from the planet. It was discovered on 9 September 1892, by Edward Emerson Barnard and named after Amalthea, a nymph in Greek mythology. It is also known as Jupiter V.
Amalthea is in a close orbit around Jupiter and is within the outer edge of the Amalthea Gossamer Ring, which is formed from dust ejected from its surface. From its surface, Jupiter would appear 46.5 degrees in diameter. Amalthea is the largest of the inner satellites of Jupiter. Irregularly shaped and reddish in color, it is thought to consist of porous water ice with unknown amounts of other materials. Its surface features include large craters and ridges.
Amalthea was photographed in 1979 by the Voyager 1 and 2 spacecraft, and later, in more detail, by the Galileo orbiter in the 1990s.
Amalthea was discovered on 9 September 1892, by Edward Emerson Barnard using the 36 inch (91 cm) refractor telescope at Lick Observatory. It was the last planetary satellite to be discovered by direct visual observation (as opposed to photographically) and was the first new satellite of Jupiter since Galileo Galilei's discovery of the Galilean satellites in 1610.
...
Wikipedia